Until comparatively recent years, seats for children's swings were of rigid heavy material such as wood or metal, but these were dangerous, especially to small children, because of the likelihood of unoccupied seats swinging into and injuring children playing or standing in the immediate vicinity.
As a result, certain lightweight seats have been developed utilizing flexible plastic material, which greatly reduce the possibility of injury to children when accidentally striking them. One such prior swing seat is disclosed in U.S. Pat. No. 3,897,056, comprising a flexible plastic seat of rectangular configuration having reinforcing spring steel straps extending along the side of the bottom surface yieldingly urging the seat toward a flat condition. Wire hangers are attached through the seat and to the ends of the straps for connection to suspending chains. This seat construction is complicated and comparatively expensive, especially due to the cost of the spring straps and the necessity of providing longitudinal series of keeper strips on the underside of the seat to retain the spring straps in position as they flex due to varying curvatures during use.
Another prior swing seat is disclosed in U.S. Pat. No. 4,478,410, comprising a flexible plastic seat also of rectangular configuration, in which laterally spaced longitudinal tubes are molded in the underside of the seat and metal chains are passed through the tubes, the outer ends of the chains being detachably connected to two suspending chains by metal clips. This construction requires the user to insert the seat chains through the tubes which is a somewhat difficult operation due to the curvature of the seat and the flexibility of the chains. Also, it is said to be safer than the construction of U.S. Pat. No. 3,897,056 because it eliminates the wire hangers of said patent and connects the ends of the seat chains directly to the suspending chains, thus providing flexible chains rather than rigid wire hangers should these parts accidentally strike a child.
This claim is somewhat questionable as the overlapping links of the seat chains and the edges of the connecting metal clips present relatively rough surfaces on contact.
Both of these prior constructions present corners and relatively sharp edges capable of injury due to their rectangular shapes.